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All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Invited review: gravitational biology of the neuromotor systems: a perspective to the next era

Earth's gravity has had a significant impact on the designs of the neuromotor systems that have evolved. Early indications are that gravity also plays a key role in the ontogenesis of some of these design features. The purpose of the present review is not to assess and interpret a body of knowledge in the usual sense of a review but to look ahead, given some of the general concepts that have evolved and observations made to date, which can guide our future approach to gravitational biology. We are now approaching an era in gravitational biology during which well-controlled experiments can be conducted for sustained periods in a microgravity environment. Thus it is now possible to study in greater detail the role of gravity in phylogenesis and ontogenesis. Experiments can range from those conducted on the simplest levels of organization of the components that comprise the neuromotor system to those conducted on the whole organism. Generally, the impact of Earth's gravitational environment on living systems becomes more complex as the level of integration of the biological phenomenon of interest increases. Studies of the effects of gravitational vectors on neuromotor systems have and should continue to provide unique insight into these mechanisms that control and maintain neural control systems designed to function in Earth's gravitational environment. A number of examples are given of how a gravitational biology perspective can lead to a clearer understanding of neuromotor disorders. Furthermore, the technologies developed for spaceflight studies have contributed and should continue to contribute to studies of motor dysfunctions, such as spinal cord injury and stroke. Disorders associated with energy support and delivery systems and how these functions are altered by sedentary life styles at 1 G and by space travel in a microgravity environment are also discussed.

Review, Tutorial↗
NASA NTRS2013

A Mission-Adaptive Variable Camber Flap Control System to Optimize High Lift and Cruise Lift-to-Drag Ratios of Future N+3 Transport Aircraft

Boeing and NASA are conducting a joint study program to design a wing flap system that will provide mission-adaptive lift and drag performance for future transport aircraft having light-weight, flexible wings. This Variable Camber Continuous Trailing Edge Flap (VCCTEF) system offers a lighter-weight lift control system having two performance objectives: (1) an efficient high lift capability for take-off and landing, and (2) reduction in cruise drag through control of the twist shape of the flexible wing. This control system during cruise will command varying flap settings along the span of the wing in order to establish an optimum wing twist for the current gross weight and cruise flight condition, and continue to change the wing twist as the aircraft changes gross weight and cruise conditions for each mission segment. Design weight of the flap control system is being minimized through use of light-weight shape memory alloy (SMA) actuation augmented with electric actuators. The VCCTEF program is developing better lift and drag performance of flexible wing transports with the further benefits of lighter-weight actuation and less drag using the variable camber shape of the flap.

Mission-Adaptive Wing↗
DOE OSTI2020

Continuous Monitoring and Partial Water Softening for Cooling Tower Water Treatment

Cooling towers are an integral component of many refrigeration systems, providing comfort or process cooling across a broad range of applications. They are the point in the system where heat is dissipated to the atmosphere through the evaporative cooling process. Cooling towers are commonly found in industrial applications and are also often used in water-cooled chilled water plants in medium to large commercial buildings. Continuous monitoring and partial water softening for cooling towers used in medium to large commercial buildings are the focus of this paper. Cooling towers consume large amounts of water. Cooling tower-related water consumption is one of largest potable water loads within buildings in the United States, with substantial building water use associated with heating and cooling. Regional water shortages have highlighted a need to reduce water consumption; the U.S. General Services Administration (GSA) and Executive Order 13834 place priority on reducing water consumption. This priority has fueled interest in the identification, investigation, and potential broad deployment of cost-effective opportunities to reduce water use, such as alternative water treatment (AWT) technologies for cooling towers. Traditional water treatment approaches use chemicals to extend the ability of the water to hold scaling minerals in suspension, minimize corrosion, and prevent biological growth. This treatment protects the chillers and cooling tower equipment; however, even when chemicals are used regularly, a certain percentage of condenser water must be drained and made up with fresh water to maintain system water quality parameters. In addition, the use of chemicals sometimes creates a waste disposal issue and can cause building owners to incur additional fees, such as disposal or wastewater charges. To manage cooling tower water treatment, GSA typically contracts with a company specializing in conventional chemical maintenance for a fixed fee. While there are many types and vendors of AWT systems, this project assesses the effectiveness of one technology provided by Aqualogix. This system is a chilled water plant monitoring and control system aimed at optimizing system performance by reducing the blowdown occurrences used to remove mineral build-up. The technology consists of two components – continuous programmable logic control (PLC) monitoring and side-stream filtration with partial water softening. PLC monitoring calculates cycles of concentration (CoC) and determines the optimum amount of blowdown water required to satisfy all water chemistry requirements. Side-stream filtration removes suspended matter and improves biocide efficacy while precisely dispensing softened water to achieve optimal makeup water hardness. Unlike other AWT systems evaluated by GSA to date, this system does not replace the legacy treatment system but is used in addition to chemical water treatment. The vendor claims their technology will reduce water consumption, water discharge, and maintenance costs. The AWT system evaluated in this demonstration is a commercialized technology. Given its commercialized state, the system evaluated in this report is at a Technology Readiness Level 9 according to National Aeronautics and Space Administration (NASA) definitions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRSDate not supplied

Selection of Alternator Voltage for Dynamic Radioisotope Power Systems

In this paper, we present a study to select an appropriate alternator voltage of the free-piston Stirling convertors (FPSC) for efficient and light Dynamic Radioisotope Power Systems (DRPS). With a system thermal-to-electrical efficiency 3-4 times greater than radioisotope thermoelectric generator (RTG) systems and a higher power density than Brayton systems in the power range of interest for radioisotope-powered systems, Stirling-based DRPS is uniquely suited to benefit upcoming NASA missions. Much effort has been invested in the design and optimization of the thermal, mechanical, and materials aspects of FPSCs, but the electrical aspect has been more nebulous. Therefore, in this paper, a preliminary study will be presented to select the appropriate Stirling alternator voltage to develop a light and efficient system using available flight components. Power conversion systems face a trade between efficiency and system volume/mass with the optimal trade being determined by the application. Neglecting non-idealities related to insulation thickness and winding packing factor and assuming a constant winding area, alternator efficiency is independent of alternator voltage. Because wire size and alternator current can be traded against turn count and alternator voltage without impacting efficiency, the guidance on the optimal design comes from analysis of the controller power electronics and the remainder of the system. Properties of available flight-qualified electrical components, such as rated voltage/current and on-resistance, typically come in discrete values instead of a continuous range of values. With multiple components being required to form the power conversion stage of the controller, each limited to incremental values, a continuous optimization is of little benefit. Instead of a continuous optimization, a random process using properties of the available components can be used to develop a Pareto design front indicating the optimized trade space. The most advantageous trade between system efficiency and mass for the system at hand can then be selected from the range of feasible designs. In the final paper, the design process, assumptions, and preliminary results will be presented.

Free-Piston Stirling Convertor Controller, Dynamic↗
DOE OSTI2023

Necessary and sufficient conditions for quadratic stabilizability of switched systems on non-uniform time domains

In this paper, we consider the quadratic stabilizability via state feedback for a particular class of switched systems that evolve on a non-uniform time domain by introducing time scales theory. The system considered switches between a continuous-time subsystem with variable lengths and a discrete-time subsystem with variable discrete step sizes. Necessary and sufficient conditions are derived to guarantee the quadratic stability of this class of switched systems via a switching state feedback law based on the existence of a common positive definite matrix satisfying the quadratic stabilizability condition by considering that the two subsystems are unstable. By state feedback, we mean that the switching among subsystems depends on the system states. Current results for this kind of state switching feedback control are derived only for switched systems evolving on a continuous time domain or a discrete time domain with fixed step’s size. These results are not applicable for the particular class of switched systems where there is a mixing between the continuous and discrete dynamics. This motivates the derivation of a new and more general state feedback control law for switched systems in this work. Here, a numerical example illustrating the results is presented.

42 ENGINEERING↗
NASA NTRS2011

Miniature, Variable-Speed Control Moment Gyroscope

The Miniature Variable-Speed Control Moment Gyroscope (MVS-CMG) was designed for small satellites (mass from less than 1 kg up to 500 kg). Currently available CMGs are too large and heavy, and available miniature CMGs do not provide sufficient control authority for use on practical satellites. This primarily results from the need to greatly increase the speed of rotation of the flywheel in order to reduce the flywheel size and mass. This goal was achieved by making use of a proprietary, space-qualified, high-speed (100,000 rpm) motor technology to spin the flywheel at a speed ten times faster than other known miniature CMGs under development. NASA is supporting innovations in propulsion, power, and guidance and navigation systems for low-cost small spacecraft. One of the key enabling technologies is attitude control mechanisms. CMGs are particularly attractive for spacecraft attitude control since they can achieve higher torques with lower mass and power than reaction wheels, and they provide continuous torque capability that enables precision pointing (in contrast to on-off thruster control). The aim of this work was to develop a miniature, variable-speed CMG that is sized for use on small satellites. To achieve improved agility, these spacecraft must be able to slew at high rate, which requires attitude control actuators that can apply torques on the order of 5 N-m. The MVS-CMG is specifically designed to achieve a high-torque output with a minimum flywheel and system mass. The flywheel can be run over a wide range of speeds, which is important to help reduce/eliminate potential gimbal lock, and can be used to optimize the operational envelope of the CMG.

Bilski, Steve↗
NASA NTRS2011

Access Control of Web and Java Based Applications

Cyber security has gained national and international attention as a result of near continuous headlines from financial institutions, retail stores, government offices and universities reporting compromised systems and stolen data. Concerns continue to rise as threats of service interruption, and spreading of viruses become ever more prevalent and serious. Controlling access to application layer resources is a critical component in a layered security solution that includes encryption, firewalls, virtual private networks, antivirus, and intrusion detection. In this paper we discuss the development of an application-level access control solution, based on an open-source access manager augmented with custom software components, to provide protection to both Web-based and Java-based client and server applications.

cybersecurity↗
DOE OSTI2025

Development of a microwave-assisted downdraft moving-bed gasifier for continuous processing of lignite and biomass chars

This research illustrates a microwave-assisted downdraft moving-bed gasifier for the first time. Such design enables continuous solid gasification process. An adjustable auger was applied to control the solid removal rate and the gas-solid interaction time. Both lignite and biomass chars were investigated to determine the capability of the current system for low-tar feedstocks with different densities. Here, the presented reactor design was able to operate continuously for 3 hours and 20 minutes under 700 ℃ and atmospheric pressure, with air as the gasifying agent. For yellow pine char, the processing rate could reach 34.1 grams per hour with decent syngas production. The downdraft moving-bed design shows better cold gas and syngas production efficiencies compared to the common fixed-bed design, due to controllable residence time and more homogeneous microwave heating. The limitations of the current design and the direction of novel microwave-assisted chemical reactor design were discussed. This novel reactor design provides a way to improve the efficiency of microwave-assisted gasification process and shows its potential to be incorporated into other established chemical reaction processes as a modular add-on.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2011

Engine Icing Modeling and Simulation (Part 2): Performance Simulation of Engine Rollback Phenomena

Ice buildup in the compressor section of a commercial aircraft gas turbine engine can cause a number of engine failures. One of these failure modes is known as engine rollback: an uncommanded decrease in thrust accompanied by a decrease in fan speed and an increase in turbine temperature. This paper describes the development of a model which simulates the system level impact of engine icing using the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k). When an ice blockage is added to C-MAPSS40k, the control system responds in a manner similar to that of an actual engine, and, in cases with severe blockage, an engine rollback is observed. Using this capability to simulate engine rollback, a proof-of-concept detection scheme is developed and tested using only typical engine sensors. This paper concludes that the engine control system s limit protection is the proximate cause of iced engine rollback and that the controller can detect the buildup of ice particles in the compressor section. This work serves as a feasibility study for continued research into the detection and mitigation of engine rollback using the propulsion control system.

May, Ryan D.↗
DOE OSTI2021

Machine learning enables national assessment of wind plant controls with implications for land use

Summary As deployment of wind energy continues to expand, computationally efficient tools for predicting wind plant performance over a wide range of layout designs, technology innovations, and spatial locations are increasingly important for policy and investment decisions. We demonstrate two approaches to training a surrogate model to predict annual energy production (AEP) of parameterized wind plant layouts: one using a Gaussian process (GP) and the other using a fully convolutional neural network (FCNN). We leverage the powerful FCNN architecture by encoding wind plant design parameters and output response surface as an image. The FCNN produces more accurate results than the GP with mean absolute errors equivalent to 1% and 1.9% of plant rated power, respectively, although the GP performs well under limited training data and provides useful uncertainty information. We also evaluate a surrogate model for wake steering, enabling a nationwide assessment of the impact of plant control strategies and plant layout decisions. Across two million locations, we find that wake steering strategies boost AEP with relative gains upwards of 3%. Gains are most pronounced at sites without a dominant wind direction and where layout optimization is less fruitful. Additionally, we perform a nationwide sensitivity analysis showing that wake steering can mitigate wake losses from higher density plant layouts. Our results suggest that regions which have not been previously viable for wind deployment due to moderate wind resources are especially well enhanced by wake steering strategies that could help overcome land constraints and inflexible layout options, potentially identifying new deployment opportunities.

17 WIND ENERGY↗
NASA NTRS2005

Discovering System Health Anomalies Using Data Mining Techniques

We present a data mining framework for the analysis and discovery of anomalies in high-dimensional time series of sensor measurements that would be found in an Integrated System Health Monitoring system. We specifically treat the problem of discovering anomalous features in the time series that may be indicative of a system anomaly, or in the case of a manned system, an anomaly due to the human. Identification of these anomalies is crucial to building stable, reusable, and cost-efficient systems. The framework consists of an analysis platform and new algorithms that can scale to thousands of sensor streams to discovers temporal anomalies. We discuss the mathematical framework that underlies the system and also describe in detail how this framework is general enough to encompass both discrete and continuous sensor measurements. We also describe a new set of data mining algorithms based on kernel methods and hidden Markov models that allow for the rapid assimilation, analysis, and discovery of system anomalies. We then describe the performance of the system on a real-world problem in the aircraft domain where we analyze the cockpit data from aircraft as well as data from the aircraft propulsion, control, and guidance systems. These data are discrete and continuous sensor measurements and are dealt with seamlessly in order to discover anomalous flights. We conclude with recommendations that describe the tradeoffs in building an integrated scalable platform for robust anomaly detection in ISHM applications.

Sriastava, Ashok, N.↗
NASA NTRS2011

Docking Offset Between the Space Shuttle and the International Space Station and Resulting Impacts to the Transfer of Attitude Reference and Control

The Space Shuttle does not dock at an exact 90 degrees to the International Space Station (ISS) x-body axis. This offset from 90 degrees, along with error sources within their respective attitude knowledge, causes the two vehicles to never completely agree on their attitude, even though they operate as a single, mated stack while docked. The docking offset can be measured in flight when both vehicles have good attitude reference and is a critical component in calculations to transfer attitude reference from one vehicle to another. This paper will describe how the docking offset and attitude reference errors between both vehicles are measured and how this information would be used to recover Shuttle attitude reference from ISS in the event of multiple failures. During STS-117, ISS on-board Guidance, Navigation and Control (GNC) computers began having problems and after several continuous restarts, the systems failed. The failure took the ability for ISS to maintain attitude knowledge. This paper will also demonstrate how with knowledge of the docking offset, the contingency procedure to recover Shuttle attitude reference from ISS was reversed in order to provide ISS an attitude reference from Shuttle. Finally, this paper will show how knowledge of the docking offset can be used to speed up attitude control handovers from Shuttle to ISS momentum management. By taking into account the docking offset, Shuttle can be commanded to hold a more precise attitude which better agrees with the ISS commanded attitude such that start up transients with the ISS momentum management controllers are reduced. By reducing start-up transients, attitude control can be transferred from Shuttle to ISS without the use of ISS thrusters saving precious on-board propellant, crew time and minimizing loads placed upon the mated stack.

Helms, W. Jason↗
NASA NTRS2014

The ISS 2B PVTCS Ammonia Leak: An Operational History

In 2006, the Photovoltaic Thermal Control System (PVTCS) for the International Space Station's 2B power channel began leaking ammonia at a rate of approximately 1.5lbm/year (out of a starting approximately 53lbm system ammonia mass). Initially, the operations strategy was "feed the leak," a strategy successfully put into action via Extra Vehicular Activity during the STS‐134 mission. During this mission the system was topped off with ammonia piped over from a separate thermal control system. This recharge was to have allowed for continued power channel operation into 2014 or 2015, at which point another EVA would have been required. Without these periodic EVAs to refill the 2B coolant system, the channel would eventually leak enough fluid as to risk pump cavitation and system failure, resulting in the loss of the 2B power channel - the most critical of the Space Station's 8 power channels. In mid‐2012, the leak rate increased to approximately 5lbm/year. Once discovered, an EVA was planned and executed within a 5 week timeframe to drastically alter the architecture of the PVTCS via connection to a dormant thermal control system not intended to be utilized as anything other than spare components. The purpose of this rerouting of the TCS was to increase system volume and to isolate the photovoltaic radiator, thought to be the likely leak source. This EVA was successfully executed on November 1st, 2012 and left the 2B PVTCS in a configuration where the system was now being adequately cooled via a totally different radiator than what the system was designed to utilize. Unfortunately, data monitoring over the next several months showed that the isolated radiator was not leaking, and the system itself continued to leak steadily until May 9th, 2013. It was on this day that the ISS crew noticed the visible presence of ammonia crystals escaping from the 2B channel's truss segment, signifying a rapid acceleration of the leak from 5lbm/year to 5lbm/day. Within 48 hours of the crew noticing the leak, an EVA was in progress to replace the coolant pump - the only other replaceable leak source. This paper will explore the management of the 2B PVTCS leak from the operations perspective. It will discuss the methodology of performing the STS‐134 refill, the considerations and contingency plans which went into the architectural overhaul of the system in 2012, and the unprecedented effort which went into the EVA response to the visible leak of May 2013. In particular the paper will focus on the techniques utilized by flight controllers to monitor the system health and to respond to such instances as the rapid May 2013 leak by putting the electrical system in a safe configuration for loss of cooling, and will use recorded telemetry of these events to describe system response to EVA crew and ground actions. It will discuss the innovative design for redundancy of the integrated truss structure's cooling systems which allowed for this leak to be managed with minimal impact to other ISS operations and electrical services, contrasted against the real unintended operations consequences of utilizing the flexibility of the spacecraft's design in this manner. The paper will discuss how the training of the crew and flight controller personnel has adapted to the changing architecture of the power system and the unpredictable nature of the 2B leak.

Vareha, Anthony↗
NASA NTRS2011

Recent Developments in the Design, Capabilities and Autonomous Operations of a Lightweight Surface Manipulation System and Test-bed

The first generation of a versatile high performance device for performing payload handling and assembly operations on planetary surfaces, the Lightweight Surface Manipulation System (LSMS), has been designed and built. Over the course of its development, conventional crane type payload handling configurations and operations have been successfully demonstrated and the range of motion, types of operations and the versatility greatly expanded. This enhanced set of 1st generation LSMS hardware is now serving as a laboratory test-bed allowing the continuing development of end effectors, operational techniques and remotely controlled and automated operations. This paper describes the most recent LSMS and test-bed development activities, that have focused on two major efforts. The first effort was to complete a preliminary design of the 2nd generation LSMS that has the capability for limited mobility and can reposition itself between lander decks, mobility chassis, and fixed base locations. A major portion of this effort involved conducting a study to establish the feasibility of, and define, the specifications for a lightweight cable-drive waist joint. The second effort was to continue expanding the versatility and autonomy of large planetary surface manipulators using the 1st generation LSMS as a test-bed. This has been accomplished by increasing manipulator capabilities and efficiencies through both design changes and tool and end effector development. A software development effort has expanded the operational capabilities of the LSMS test-bed to include; autonomous operations based on stored paths, use of a vision system for target acquisition and tracking, and remote command and control over a communications bridge.

Dorsey, John T.↗
DOE OSTI2018

Phase Equilibria in the ZnO-“FeO”-SiO{sub 2} System in Reducing Atmosphere and in the ZnO-“FeO”-SiO{sub 2}-“Cu{sub 2}O” System in Equilibrium with Liquid Copper Metal at 1250 °C (1523 K)

Recent experimental studies in the ZnO-“FeO”-SiO{sub 2} system in reducing atmosphere demonstrated significant discrepancies with the current FactSage thermodynamic model developed using previous experimental data in this system in equilibrium with metallic iron and air. The present experimental study on phase equilibria in the ZnO-“FeO”-SiO{sub 2}-“Cu{sub 2}O” system in equilibrium with liquid copper at 1250 °C (1523 K) at low copper oxide concentrations in slag was initiated and undertaken to resolve these discrepancies. A high-temperature equilibration–rapid quenching–electron-probe X-ray microanalysis (EPMA) technique using a primary phase substrate support and closed system approach with Cu metal introduced to determine effective equilibrium oxygen partial pressure from the Cu{sub metal}/Cu{sub 2}O{sub slag} equilibria was applied to provide accurate information on the liquidus and corresponding solid compositions in the spinel, willemite, and tridymite primary phase fields. The present results confirmed the accuracy of the FactSage model, resolved discrepancies, and demonstrated significant uncertainties in the recent studies by other authors on the system in the open reducing atmosphere. The present study shows how this closed system approach can be used to obtain key thermodynamic data on phase equilibria in systems containing volatile metal species, overcoming the limitations and uncertainties encountered in conventional open gas/condensed phase equilibration with these systems. The study highlights the importance of the focus on obtaining accurate experimental data and the risks of misleading information from inadequate experimental control and analysis. The study also demonstrates that continuing in-depth critical review and analysis of the elemental reactions taking place in complex systems is an essential step in phase equilibrium research.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Pore space partition of metal-organic frameworks for gas storage and separation

Pore space partition (PSP) concept is a synthetic design concept and can also serve as a structure analysis method useful for next-step synthetic planning and execution. PSP provides an integrated chemistry-topology-focused tool to design new materials platforms. While PSP is no less effective for making large-pore materials, the growing importance of small-molecule gas storage and separation for green-energy applications provides impetus for developing small-pore materials for which the PSP strategy is uniquely suited. Currently, the best embodiment of the PSP concept is the partitioned-acs (pacs) platform in which both fine or coarse adjustments to the building blocks have sparked a transformation of a prototype framework into a huge and continuously expanding family of chemically robust materials with controllable pore metrics and functionalities suitable for tailored applications. The pacs compositional diversity results from the platform’s intrinsic multi-module nature, geometric flexibility and tolerance towards individual module variations, and mutual structure-directing effects among various modules, all of which combine to enable the molecular-level uniform co-assemblies of chemical components rarely seen together elsewhere. Here, in this contribution, we present an overview of different pore space engineering methods and how different MOF materials have contributed to important advances in chemical stability, industrial gas storage and gas separation. In particular, we will focus on synthetic assembly of the pacs system, highlighting the differences of pacs materials from other MOF platforms and advantages of pacs materials in enhancing various MOF properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Risk to ecological resources following remediation can be due mainly to increased resource value of successful restoration: A case study from the Department of Energy's Hanford Site

Several nations are faced with the need to remediate large contaminated sites following World War II, the Cold War, and abandoned industrial sites, and to return them to productive land uses. In the United States, the Department of Energy (DOE) has the largest cleanup challenge, and its Hanford Site in the state of Washington has the most extensive and most expensive cleanup task. Ideally, the risk to ecological resources on remediation sites is evaluated before, during, and after remediation, and the risk from, or damage to, ecological resources from contaminants should be lower following remediation. In this paper, we report the risk to ecological resources before, during, and as a consequence of remediation on contaminated units requiring cleanup, and then examine the causes for changes in risk by evaluating 56 cleanup evaluation units (EUs) at the Hanford Site. In this case, remediation includes a restoration phase. In general, the risk to ecological and eco-cultural resources is currently not discernible or low at most contaminated units, increases during remediation, and decreases thereafter. Remediation often causes physical disruption to ecosystems as it reduces the risk from exposure to contaminants. Most new remediation projects at the Hanford Site include ecological restoration. Ecological restoration results in the potential for the presence of higher quality resources after remediation than currently exists on these contaminated lands and facilities. Although counter-intuitive, our evaluation of the risk to ecological resources following remediation indicated that a significant percentage of units (61%) will be at increased risk in the post-remediation period. This increased risk is due to DOE's successful remediation and restoration that results in a higher percent of native vegetation and higher ecological value on the sites in the post-remediation period than before. These newly-created resources can then be at risk from post-remediation activities. Risks to these new higher quality resources include the potential for spread of invasive species and of noxious grasses used in previous cleanup actions, disruption of ecosystems (including those with state or federally listed species and unique ecosystems), compaction of soil, use of pesticides to control invasive species, and the eventual need for continued monitoring activities. Thus, by greatly improving the existing habitat and health of eco-receptors, and maintaining habitat corridors between high quality habitats, the ecological resources in the post-remediated units are at risk unless care is taken to protect them. Many of the negative effects of both remediation and future monitoring (or other future land uses) can be avoided by planning and management early in the remediation process. We suggest DOE and other agencies convene a panel of managers, remediation scientists, regulators, environmental and ecological scientists, Native Americans, economists, and the public to develop a generic list of performance metrics for the restoration phase of remediation, including evaluation of success, which could be applied across the DOE complex.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Long-Term Cancer Outcomes From Study NRG Oncology/RTOG 9517: A Phase 2 Study of Accelerated Partial Breast Irradiation With Multicatheter Brachytherapy After Lumpectomy for Early-Stage Breast Cancer

Purpose: To examine 10-year rates of local, regional, and distant recurrences, patterns of recurrence, and survival rates for breast cancer patients enrolled on Study NRG Oncology/Radiation Therapy Oncology Group 9517, a multi-institutional prospective trial that studied one of the earliest methods of accelerated partial breast irradiation (APBI), multicatheter brachytherapy (MCT). Methods and Materials: Eligibility included stage I/II unifocal breast cancer <3 cm in size after lumpectomy with negative surgical margins and 0 to 3 positive axillary nodes without extracapsular extension. The APBI dose delivered was 34 Gy in 10 twice-daily fractions over 5 days for high-dose-rate (HDR); and 45 Gy in 3.5 to 5 days for low-dose-rate (LDR) brachytherapy. The primary endpoint was HDR and LDR MCT reproducibility. This analysis focuses on long-term ipsilateral breast recurrence (IBR), contralateral breast cancer events (CBE), regional recurrence (RR), and distant metastases (DM), disease-free, and overall survival. Results: The median follow-up was 12.1 years. One hundred patients were accrued from 1997 to 2000; 98 were evaluable; 65 underwent HDR and 33 LDR MCT. Median age was 62 years; 88% had T1 tumors; 81% were pN0. Seventy-seven percent were estrogen receptor and/or progesterone receptor positive; 33% received adjuvant chemotherapy and 64% antiendocrine therapy. There have been 4 isolated IBRs and 1 IBR with RR, for 5.2% 10-year IBR without DM. There was 1 isolated RR, 1 with IBR, and 1 with a CBE, for 3.1% 10-year RR without DM. The 10-year CBE rate was 4.2%, with 5 total events. Eleven patients have developed DM, 8 have died of breast cancer, and 22 have died from other causes. The 10-year DFS and OS rates are 69.8% and 78.0%, respectively. Conclusion: This multi-institutional, phase 2 trial studying MCT-APBI continues to report durable in-breast cancer control rates with long-term follow-up.

62 RADIOLOGY AND NUCLEAR MEDICINE↗